Resistance-based random access memory devices use a variable resistive material to store data. The variable resistive material has a resistance that can be changed responsive to a programming voltage. For example, a storage element of a resistance-based random access memory device may be programmed to a first resistance state to indicate storage of a first logical value (e.g., a low resistance state representing a “0” value) and may be programmed to a second resistance state to indicate storage of a second logical value (e.g., a high resistance state representing a “1” value).
Storage elements of a resistance-based random access memory device can be arranged in a three-dimensional structure. In such a structure, each storage element may be placed between a bit line and a word line. For example, a first storage element may be coupled to a first bit line and to a first word line. A second storage element may be coupled to the first bit line and to a second word line. Another storage element may be coupled to a second bit line and the first word line. In this arrangement, to read the first storage element, a read voltage may be applied across the first storage element by applying a first voltage (e.g., a relatively high voltage) to the first bit line and applying a different voltage (e.g., a relatively low voltage) to the first word line. A sense amplifier coupled to the first bit line may sense current (e.g., a “read current”) that flows through the first bit line. The current flowing through the first bit line is responsive to the voltage across the first storage element. Thus, the current can be used to determine a resistance state of the first storage element using Ohm's law.
Since the storage elements of the resistance-based random access memory device store logical values based on resistance state, different read currents may indicate different logical values. For example, reading a storage element that is in a low resistance state uses more read current than reading a storage element that is in a high resistance state. Reliability of data storage and retrieval at the resistance-based random access memory device may be impacted due to the resistive network topology of the memory, such as by introducing leakage current during read operations.